SEPTEMBER Vol.2 Issue 4
Altair 7000 Graphics Printer
The tremendous flexibility of the 7000 Graphics /Printer,
which acts as a printer, plotter and graphics device, makes
it one of the fastest and most economical methods of electro-
static printing. The new Universal I/O board for the Altair
680b expands the I/O capabilities of the 680b beyond the
one serial port on the main board. Thanks to the 88-Mux
(24 Channel Multiplexer), the input capacity of the 88-
Analog-to-Digital Converter for applications requiring a
large number of analogs has been greatly increased. The
new 88-S4K Memory Board now makes totally synchronous
memory logic available to Altair 8800 users.
The 7000 Graphics/Printer
Although there are a number of methods used for
printing computer output, electrostatic printing is
finally being recognized as the only method which is
fast, economical and, now with the MITS 7000, is also
the most flexible means. In last month's G.N. we
introduced the 7000 Graphics/Printer as a multifunc-
tion, hard-copy output device which is plug compatible
with the 680 and 8800 mainframes via one PI0 port.
The enthusiastic response to the 7000 warrants a more
detailed explanation of its operation and applications.
The flexibility of the 7000 is due to eight print
electrodes, driven directly by software, instead of
the usual seven found in 5 x 7 matrix printers . Copies
made from the printed output are actually more legible
than copies of typed paper and can be made for about
1$ per foot of electrosensitive paper.
When the 7000 is used as a line printer, char-
acters are generated using a 5 x 7 dot matrix. Altair
BASIC supports three different sizes of character sets
(each with upper and lower case) to produce line
widths of 20, 40 or 80 characters in the four-inch
wide printing area. The speed is 160 characters per
second (80 characters per line) or 120 lines per min-
ute. Different character sizes are selected with the
CHR$ function in BASIC.
The eighth or extra printing electrode in this
unit provides symmetry along the horizontal and verti-
cal axes to permit plotting. With the vertical dis-
tance between electrodes equal to the distance between
lines, there's no gap from line to line. This special
feature makes the 7000 ideal for graphics. Pictures
can be produced that show either a distinct outline or
a sophisticated, detailed picture with shaded areas.
When the eight-dot columns are printed close together,
— Continued on Page Four -
Keeping up with its innovative tradition, MITS
has recently announced several new
products which will greatly expand the capabilities
of the Altair Computer
■-,"' v . '■
j .-, ■? * , .a ■ , 4/ . < s - ■.
- ^'^W^W^^^m^m W0: pp ili
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: 5ife* 1.1
Hfitil i|< i^il i Wliafll i i '•■ ■ :=!
680 -b Universal I/O Board
88 - Multiplexer
88 - S 4k Memory Board
Letters to the Editor
tot. La/uty B, CoWull o& Vqj> MoinoA, lorn., &2.wt In the. laltowlnQ
comments on Hen/iy A/moid 1 4 Blofihythm Pfwgiam [ ComputeA HotoA, Juty,
The calculations of Yl and Y2 are incomplete. The program as
listed on page ten of the July issue assumes that any year which is an
integer multiple of four is a leap year. The correct leap year rule
is: any year 'evenly' divisible by four is a leap year UNLESS it is
•evenly' divisible by 100 (a 'century' year), BUT it is still a leap
year if it is 'evenly' divisible by 400. To. correct the program,
rewrite the lines shown here:
5000 IF INT(Y1/4)*4<>Y1 THEN 5200 ;N0T A LEAP YEAR
5100 IF INT(Y1/100)*1QQ=Y1 AND INT(Yl/400) *400<>Y1 THEN 5200 ;N0T A LEAP YR
5150 Ll=l: GOTO 5300
5200 LI =0
5300 IF INT(Y2/4)*4<>Y2 THEN 5500 ;N0T A LEAP YEAR
5400 IF INT(Y2/100)*100=Y2 AND INT(Y2/400)*400<>Y2 THEN 5500 ;N0T A LEAP YR
5450 L2=l: GOTO 5600
10510 IF INT(Y2/4)*4oY2 THEN 10530 ;N0T A LEAP YEAR
10520 IF INT(Y2/100)*100=Y2 AND INT(Y2/400)*400<>Y2 THEN 10530 ;N0T A LEAP YR
10525 L2-1: GOTO 10600
Note that lines 5200, 5500 and 10530 need not be re-written; lines
5150, 5450 and 10525 are added lines. These changes will allow the
program to work correctly for persons born before March 1, 1900. The
leap-year rule stated above is correct for any year later than 1582,
when the Gregorian calendar was adopted as a long-needed reform.
Dear Ed. ,
In the last issue of Computer
Notes , you mentioned a number of mag-
azines interested in articles on
microcomputers (and willing to pay
for them). We are too, i.e., seek-
ing good articles and willing to pay.
In particular, we're interested in
first person experience building com-
puter kits and peripherals, and then
getting them operational. But even
more, we're trying to focus on "what
do you do with it after it's built?"
That is, applications. Things like
a file system for LP records, menu/
shopping planning for various tasks
and dietary requirements, kinetic
video art, and, of course, games.
But challenging games, cybernetic
games, learning games.
Contributions should be sent to
Ms. Burchenal Green, Editor, Creative
Computing, P.O. Box 789-M, Morristown,
David H. Ahl,
- Continued on Page Fifteen -
~- 4 'mim
By Gale Schonfeld
This month the Repair Department has
asked me to relay the following message
WARRANTY ON MITS PRODUCTS
The warranty on kits is 90
days for parts. Labor is charged
at $22.00 per hour for all com-
puter mainframes and related
products. The warranty on assembled
items is 90 days for parts and
For detailed information on
product warranty, please check your
manuals. Remember - the warranty
does not cover postage and handling
to and from the MITS factory.
HOW TO SHIP UNITS IN FOR REPAIR
Packing - Make sure when pack-
ing items to be returned for repair
that all accessories are secured in
place and that they are not "float-
ing" inside or outside of the main-
frame. Transformers should be
bolted down or shipped separately,
peripheral boards should be secured
in their card guides and edge con-
nectors, or packed in a separate
box, disk drives must have the
"block" secured in place, etc.
Damage resulting from poor packing
or packaging will automatically
void your warranty . The Repair
Department will advise you of any
packing damage before repair action
Packaging - If at all possible,
items should be shipped in the orig-
inal MITS box, padded well with
newspaper or styrofoam beads.
Styrofoam corner pads should be
used to protect mainframes and ter-
minals. Double boxing is preferred.
Damages caused by the shipping
agent - If an item received appears
to have been damaged in shipment,
the Repair Department will immed-
iately contact the customer so that
appropriate action may be taken for
Mailing labels - Please be
sure that your mailing label reads
"ATTN:. Repair Department". We do
have several departments which re-
ceive in-coming packages and unnec-
essary delays can be caused by mis-
Enclose a letter - Please be
sure to enclose a letter explaining
the problems you are having with your
equipment. Examples of these pro-
blems would also be helpful. Also,
please remember to state who the
actual owner of the computer or per-
ipherals is (the owner, by our
records , is the person or company
listed in the "sold to" address on
your invoice) . We ask this in order
to prevent unnecessary charges due
to lack of information on warranties.
Labor Charges - Labor charges
are rated at $22.00 per hour for all
mainframes and related products.
-Continued on Page Fifteen -
TreKMng with the Altalr
By Steve Lowe of Microsystems,
At the recent "STARTREK EXPO"
held at the Hyatt Regency Hotel in
Washington, D.C., MICROSYSTEMS was
on hand with an impressive display
of ALTAIR computers to introduce
"Trekies" to the world of micro-
computers. Several ALTAIR computer
systems were displayed featuring a
disk system, a talking ALTAIR, a
T.V. Dazzler system using an Advent
4' x 6' Videobeam T.V., and a game
system using a second Videobeam T.V.
as a terminal.
Throughout the three day event,
each of the systems proved their
worth in attracting and holding
convention-goers' attention while
the MICROSYSTEMS staff answered
questions and provided information
to interested people. Many had no
idea that microcomputers were so
versatile and later dropped in at
the MICROSYSTEMS showroom for more
in-depth demonstrations of MITS
computers and ALTAIR BASIC.
One highlight of the show for
the MICROSYSTEMS crew was a visit
to their display by several of the
original stars of the STARTREK T.V.
series. George Takei, who plays
Mr. Sulu in the series, was lured
into the display room and tried out
different versions of STARTREK
games in front of a large crowd.
During one game where the Enter-
prise engages in combat with a
similarly armed Klingon Vessel,
George asked, "Do we have to fight?
Why can't we negotiate?" Moments
later a moan of anguish engulfed
the room as the crowd watched the
Klingon ship out-maneuver and des-
troy the USS Enterprise. George
redeemed himself, however, by win-
ning his second battle. A newcomer
to the world of microcomputers, he
admitted that he could understand
the fascination that made the
MICROSYSTEMS display such a popular
attraction at the show. Even before
Gene Roddenberry (the producer of
Star Trek) spoke later that day
about the impact of computers on
the future of humanity, MICROSYSTEMS
had been proving that thanks to
MITS, the impact of computers is
already being felt around the world.
Moments before the Klingon' s des-
troyed the Enterprise, George Takei
(Mr. Sulu from the Star Trek T.V.
series) pauses to ask the MICRO-
SYSTEMS crew about "the possibility
of negotiating with the Klingon
By Linda Blocki
RIDDLE : What does a medical
center, the Senate Watergate Com-
mittee's investigative team and a
Tibetan monastery have in common?
ANSWER: a computer. Surprised?
Thanks to new electronic develop-
ments, the use of computers is
quickly expanding to practically
all areas of everyday American life.
Information about computers is
no longer confined to complicated
articles by mathematicians and data
processors. Many noncomputer spec-
ialists are now doing some inter-
esting research and writing, which
is gradually replacing the public's
confusion about all that hardware
and software with beneficial infor-
mation that anyone can understand.
The Compleat Computer (1976),
a carefully compiled collection of
over 100 informative and sometimes
humorous articles by noncomputer
specialists, seems to be the best
publication so far to help expose
people to the many diverse opinions
about the use of computers. Author
Dennie Van Tassel, user liaison in
the computer center at UCSC and col-
lector of computer miscellany, has
filled his paperback book with a
wide variety of selections from fic-
tion, poetry, newspapers, cartoons,
and advertising as well as more
detailed articles that concern the
computer specialists. Such well-
known noncomputer experts as Norman
Cousins, Ray Bradbury and Isaac
Assimov are just a few of the writers
whose articles appear throughout the
Some of the different areas
the articles cover include the story
of a fully computerized poison con-
trol center in a children's hospital
in Missouri, a fictional account of
a Tibetan monastery that used a Mark
V computer to compile a list of all
the possible names of God and a
computer which acted as a key "mem-
ber" of the Senate Watergate inves-
tigative team by spewing out minute
facts about any witness in a frac-
tion of a second.
In order to include as much
material as possible, Van Tassel
has capsulized the longer articles
and selected only the "tastiest
tidbits" for publication. His ex-
tensive references following each
article are helpful to the inter-
ested reader who wishes to pursue
a topic in greater depth. After
each well-organized section of the
book, a long list of questions and
exercises is included to further
aid the reader in exploring other
various opinions about the use of
The book is divided into nine
sections starting with three intro-
ductory chapters — "In the Beginning,"
"How Computers Do It" and "The
Software"- -which discuss the basics
of computer operation. Articles
appearing in this first section in-
clude "The Development of Automatic
Computing," "Computer Games People
Play" and "Technology, McDonald's
Collide as Students Best Burger
Bonanza," a humorous article des-
cribing how Cal Tech students used
an IBM computer to print out 1.2
million entry blanks and win a
Continued on Page Fourteen
- Continued from Page One —
the effect is a very dark image.
When the columns are printed farther
apart, the image appears lighter.
The 7000 is controlled by using
a single port on an 88-4PIO parallel
interface board. One section of the
port provides the eight bits of in-
formation to be printed, and the
other section provides control.
The control signals to_ the 7000
are: (1) MOTOR ON, which starts the
motor running while the print head
remains disengaged, (2) PRINT, which
engages the print head to begin tra-
veling across the page and (3) LINE
FEED, which causes a line feed with
no print head movement.
The control signals from the
7000 are: (1) CT or character timing
pulse. The first pulse defines the
left-hand margin once the print head
has begun to move, (2) DT or dot
timing pulse. There are eight dot
pulses for each character pulse.
Each time a new column of in-
formation is to be printed, the
appropriate data bits are forced low
(logic "0") by the 4PI0. Each low
data line causes the related print-
head electrode to discharge to the
paper. This produces one dot. In
all there are more than 500 eight-
dot columns in a line.
To print characters, seven elec-
trodes are used to provide a one-dot
space between lines. In the plot
mode all eight electrodes are used
so that there's no space between the
lines that make up a plot.
The software required to use the
Altaif 7000 Graphics/Printer as a
line printer has been integrated into
the BASIC interpreter. In order to
list or print using the 7000, the
LPRINT or LLIST commands are used.
In order to change the character
size, an LPRINT command must be
issued which includes one of the
following three special characters:
prints 80 characters/ line
prints 40 characters/ line
prints 26 characters/ line
LPRINT CHR$(1); "TEST SMALL CHARACTERS"
LPRINT CHR$(2);"TEST MEDIUM CHARACTERS"
LPRINT CHR$(3);"TEST LARGE CHARACTERS"
produces the following output:
Note : If a new character size is
not requested, the most recently
requested character size will be
Except for one assembly lan-
guage subroutine, the software for
using the Altair 7000 Graphics/
Printer as a plotter is written
entirely in BASIC language. This
will allow the user to make his own
custom modifications to the standard
software. It will also allow him to
save room in memory by removing sub T
routines that are not required.
The image to be printed is
stored in memory in a buffer with
each bit representing a dot in the
picture. If the bit is turned on,
the corresponding dot is present.
If the bit is turned off, the cor-
responding dot is absent. A 256
byte segment of memory represents
the 8 rows of 256 dots printed on
one pass of the print head. In
order to cause this 8 by 256 segment
to be printed, a single call to the
assembly language routine is re-
Since an 8 by 256 dot picture
is far too small to be of any prac-
tical use, the plot routine uses a
number of these 8 by 256 elements to
compose a picture. The standard
number is 32, and this requires an
8K buffer for the image. The user
may increase or decrease this number
by altering a single BASIC statement
as his heeds require or his memory
There are BASIC subroutines
1) performing initialization - set-
ting buffer size, location, etc.
printing the entire buffer
clearing the buffer
4) marking a dot
5) writing a character
writing a string for label
calculating scaling factors
plotting a point
drawing a line
Here is some sample output: r]
7000 Graphics/Printer Specifications:
Price and availability: $785, 60
Printing medium: Electrosensitive
paper -?(5 inches
..; '. '• vide) '■*
A. Internal timing-
B. External timing-
better than 128
0.0175 inches/msec . +
Timing markers: A.
Every 1/80 inch
Every 1/10 inch
Plotting speed: Two lines per second,
8 dots vertical
Input raster: Eight-bit parallel
Power: 115V AC. 36 VA
Weight: 14 lbs.
Interface: 1 PIO Port (88-4PI0 or
parallel port on 680b
Universal I/O Board)
The 680b Universal I/O Card :
The 680b Universal I/O card
provides two parallel ports and one
serial port to greatly enhance the
I/O capabilities of the Altair 680b
while occupying only one slot on
the expander board.
The design of the Universal
I/O's two parallel ports is based
upon a Peripheral Interface Adapter
(PIA). The PIA contains all control
and data registers, thus most options
are software selectable. These op-
tions include data direction (each
data line can act as an input or an
output), and interrupt/control struc-
ture. The Universal I/O can be ex-
panded up to two parallel ports.
Parallel Port Selection:
Each Universal I/O card requires
16 address lines. Hardware sets the
upper 8 address lines (A15 to A8)
to F0 (hexadecimal) for all 1/0
ports. These addresses are F0XX.
Address lines A 7 through A4
and their complements A7 through A4
are user-selectable. With these
addresses there are 16 different
address locations for the Universal
I/O (4 addresses are reserved for
future use) .
Address lines A3 and A2 select
between 3 ports. A3 addresses the
parallel ports or the serial port.
A2 selects a particular parallel
Each PIA contains 2 sections.
Sections A and B each contain two
channels, control status channel
and data-data direction channel.
Address lines A0 and Al enable the
selection of port section, A or B,
and the selection of control status
channel or data channel. If the two
parallel ports are addressed at F008
and F00C, the port, section and
channel addresses would appear as
(Refer to Figure One)
The following block diagram illustrates the internal
structure of a PIA,
I/O DEVICE (S)
(Refer also to "Software Initializa-
tion of Parallel and Serial I/O
Boards" by Patrick Godding, Computer
Notes, June, 1976, pp. 14-17.)
All lines are switch-selec-
table for RS-232, TTL levels or
20 milliamp current loop (TTY) .
The serial port is programmable
for nine or ten bit transmission
a. 7 data bits .+ parity bit (odd,
even, or none) + 1 or 2 stop
b. 8 data bits + 1 or 2 stop bits;
c. 8 data bits + 1 stop bit +
parity bit (odd or even)
The transmit and receive inter-
rupts enable or disable under soft-
ware control. The Universal I/O
provides an onboard, crystal-
controlled clock that allows user
selection for any of 13 baud rates
by positioning a dip switch.
The Selectable Baud rates are:
Universal I/O Board Specifications :
Level Selection: Switch selectable,
TTL, RS232, TTY
generator (ACIA) : Crystal-controlled
(fully expanded) 12
conductor cable, 10-
pin removable connec-
tor on board and 25
pin connector (ACIA) .
Three removable flat
cables with a 24-pin
plug on the board and
a 25-pin connector
passed through the
back panel (for PIAs
and other parallel
680b Mb slots: One
The Universal I/O with only one
PIA parallel port can handle two in-
puts (such as a paper tape reader
or keyboard) or two output devices
(such as a paper tape punch and
printer) or any combination of cus-
tom applications. A Universal I/O
with two PIA parallel ports has 32
data lines (each group of eight is
individually selectable). All data
lines are fully TTL compatible.
Eight of the 16 lines are capable
of directly driving the base of a
transistor switch (1.5v at lma) .
The design of the Universal
l/0*s serial port is based upon an
Asynchronous Communications Inter-
face Adapter (ACIA). The ACIA allows
serial data to be taken in on its
receive line and transfers the data
onto the Data Bus, or data can be
entered from the data bus into the
ACIA and then sent out the transmit
data line in serial form.
The ACIA contains both control
and status iregisters. Five control
lines allow maximum utilization of
sophisticated terminals. The five
control lines are: (1) transmit
data, (2) receive data, (3) data
carrier detect, (4) clear to send
and (5) request to send.
The 8-bit Status Register
allows for greater control and
handshaking ability by indicating
received data available, trans-
mitter buffer empty, carrier de-
tect, clear to send., . framing (error,
received data overflow, parity
error, and interrupt request.
Power: +5 volt at approximately
350 milliamps fully ex-
panded. Typically 27 mil-
liamps @ +16 volts. Typi-
cally 10 milliamps @ -16
table for seven
or eight bits,
one or two stop
bits and odd or
even parity PIA.
88-S4K Memory Board :
An ideal addition to the Altair
8800 series computer is the 88-S4K
Synchronous 4K Memory Board, which
has many outstanding features in-
cluding totally synchronous design
logic. This means the memory re-
lies solely on the CPU for timing
signals - no single shots and no
critical on-board timing.
•Continued on Page Nine— Page Five
Troubleshooting the 680b
by Rich Haber
We have been very impressed in the repair department by how few
680b 1 s have been sent back to us. Kit builders have been doing a really
good job assembling and troubleshooting their units. If you are having
any trouble with your 680b, the troubleshooting aids on pages 17-19 in
the Theory of Operation Manual will help you track down some of the most
Apparently not everybody received or noticed the errata sheet
explaining that Q2 and Q3 and Q100 were silkscreened incorrectly on some
of the main boards. The emitters were marked where the collectors should
be and vice versa. The correct positioning for these transistors is
shown in Figure 1. There was also an error on page 30 of the Assembly
Manual and page 10 of the Operator's Manual concerning the Baudot inter-
face. The values for R401 and R400 were reversed and a diode (D402) was
left out. See Figure 2 for the correct configuration.
Here is a list of some common problems with the 680b and how to
track down the causes.
- AO , .._D402
(Di spl ay/Control Board)
#1 - Capacitor C7 should be ommitted
and resistor R75 should be re-
placed by a jumper wire. This
filter circuit is not necessary
since it will attenuate the 02
input to IC SI -3 too much.
#2 - When installing the resistor
pack (page 5-24) it is necessary
to clip off the last three leads
at the end furthest from the dot
on the resistor pack. There are
no holes on the PC board for these
leads and these three resistors
1. All address lights except AO lit.
This indicates that the computer is lo cked in the reset mode. This
can be verified if pin 40 of the MPU (RES) is LOW. Probable causes:
Q2 and Q3 are in backwards (silkscreen shows C § E reversed)
Solder bridge on transistor lands.
No phase 1 clock signal to IC K pin 10 on front panel. If
true, then check pin 2 of IC pp.
Bus line 54 shorted.
2. MPU always running.
This can be verified if pin 2 of MPU (HALT) is HIGH,
a. No 02 phase 2 clock signal to IC K pin 2 to retrigger the one-
shot; if so, then check PP-4.
b . IC I or K defective (check logic) .
c. Q4 or Q5 in backwards, shorted or defective.
3. Can't deposit.
Make sure RAMs are strapped to the address you want.
Check to see if pin 34 of the MPU (R/W) goes LOW when the deposit
switch is toggled. If 34 won't go LOW, look at 1-12 on front
panel and trace back.
BA (pin 7 of MPU) should be HIGH.
IRQ (pin 4 of MPU) should be HIGH.
IC M pin 12 should be HIGH for read, pulse LOW for deposit.
Does 02 appear at pins 1 and 2?
AA-8 should be LOW. If not, and all AA inputs are HIGH, look
for a short on this line.
Check for solder bridges on RAMs.
4. Can't deposit at any one bit.
First interchange RAMs and see if bad bit changes. If it does, then
the RAM is bad. If not, make the following checks on the bad bit
(leftmost RAM is bit 0):
a. Pin 13 should be LOW.
b. Pin 10 should be HIGH.
c. Pin 3 should be HIGH to read and pulse LOW to write.
d. Is data appearing at DI (Pin 11)? Is data appearing at DO
(Pin 12)? If not, check logic at NAND gate and inverter on
output (pin 12) . Outputs of NAND gates should be HIGH for a
"1" and LOW for a "0"
Failure here could involve laborious
tracing for solder bridges or shorted IC. _ c on tinued -
Check pin 14 of PROM (chip select). It should go LOW when reset is
toggled. If not, check to see that: DD8 is LOW, GG13 is HIGH, HH4
is LOW and NN40 is LOW while resetting.
If the monitor fails to print a period, it is occasionally due to
two or more addresses being shorted together. Toggle each address
switch separately to see if the LED lights. If a LED fails to
light, position all the address switches up. If the LED comes on,
then there is a short between addresses. You can isolate which one
by putting the switches down one by one.
Pins 2 and 6 of the ACIA should be HIGH after initializing the moni-
tor (with 680b in terminal option), otherwise a short is indicated.
Pins 3 and 4 should have a square wave signal equal to 16 times the
baud rate; look for a .568 msec, period for 110 baud, .208 msec,
for 300 baud. NOTE: R15 should be IK ohm instead of 4.7K. Do not
bother to replace it unless the voltage at the right side of R15 is
below TTL levels. If the voltage is very low, IC Z is probably bad.
The most common causes of problems on units we have received have
a. Solder bridges and cold solder joints (especially on 100 pin
b. Incorrect parts placement
c. Incorrect hardwire strapping
d. IC pins bent under chip
I would like to recall your attention to the problem mentioned in the
June Computer Notes ("Altair 680b Hardware Notes," page 9). If the
MPU is given an invalid instruction to execute, it cannot be reset
through the front panel switch. Instead, power must be turned off
and on and then RESET must be activated, thereby erasing memory. To
correct this, do the simple modification that is outlined in the
Here is a convenient check list of logic levels for troubleshooting:
Status (MPU Stopped)
HIGH (pulses LOW
cy = 16 x baud rate
tied to A0
HIGH (pulses LOW
same as front
same as front
LOW when addressed
LOW when addressed
Continued on Page Ten
01 (phase 1 clock)
IRQ (interrupt request)
VMA (valid memory)
NMI (non maskable
BA (bus available)
02 (phase 2 clock)
ACIA J J
clock square wave freque
CS2 (chip select 2)
RS (register select)
DI (data in)
DO (data out)
CS (chip select)
CS (chip select)
2320 N. 56th Lane
Fort Smith, Arkansas
Ronald W. Moore
A Div. USS America CV66
FPO, New York 09501
Robert M. White
5240 Kootenai St.
Boise, Idaho 83705
Cary, IL 60013
New Address for:
Capt. James K. Bostick
Tuslog DET II
PSC Box 2324
APO, New York 092.24
420 Bankcroft Ct., #8
Rockford, IL 61107
David M. Fogg, President
4223 S.W. Fwy. , #203
Houston ,VTX 77027
The HAMCC meets on the second Friday
and the fourth Tuesday of each
Anyone interested in forming a club
in the Rockford, Illinois, area
420 Bancroft Ct., #8
Rockford, IL 51107
MITS is pleased to announce the development of a 16K static card for the
Altair 680b. With an access time of 215 nanoseconds and low power consumption of
5 watts, we feel that this is an excellent addition to the Altair 680b.
To sweeten the pot even more, we are including a free copy of Altair 680 BASIC,
assembler, and text editor on paper tape. ($275 value)
Altair 680 BASIC is identical to the 8K BASIC developed for the Altair 8800.
Features include Boolean operators, the ability to read or write a byte from any I/O
port or memory location, multiple statements per line, and the ability to interrupt
program execution and then continue after the examination of variable values.
Other features of Altair 680 BASIC include variable length strings (up to 255
characters), with LEFT$, RIGHTS and MID$ functions, a concatenation operator
and VAL and STR$ to convert between strings and numbers. Both string and
numeric arrays of up to 30 dimensions can be used. Nesting of loops and subroutine
calls is limited only by available memory. Intrinsic functions include: SIN, COS,
TAN, LOG, EXR SQR, SGN, ABS, INT, FRE, RND and POS, in addition to TAB and
SPC in PRINT statements. Altair 680 BASIC takes 7K bytes of memory.
MITS has also developed an expander card for the Altair 680b that lets you add up
to three boards inside the main case. Read "Computer Notes" for announcements
of additional Altair 680b boards.
Altair 680-BSM, 16K Static Memory Board, including Altair 680 BASIC, assembler
and text editor $685.00 kit
Altair 680-MB Expander Card with one Edge Connector $24.00 kit
Altair 680 BASIC (purchased separately) $200.00
Altair 680 assembler and text editor (purchased separately) $ 75.00
PRICE APPLIES ONLY TO PURCHASERS OF ALTAIR 68OD COMPUTER
Prices, specifications subject to change. Allow 30-60 days for delivery.
MITS, Inc. 2450 Alamo S.E. /Albuquerque, New Mexico 87106
- Continued from Page Five -
There are no wait states so that the
CPU runs at maximum speed.
The 88-S4K provides 4,096
bytes of Random Access Memory while
consuming very low power. Each
board contains memory protect cir-
cuitry and address selection cir-
cuitry for any one of 16 starting
locations in increments of 4K.
The 7 entire 4,096 bytes of memory
can be protected by switching to
PROTECT. A DIP switch is used for
board selection with no hardwire
jumpers, and test points have been
installed at important signal out-
puts for ease of checkout and
troubleshooting. Ferrite beads
are used on all common supply lines
for noise isolation.
For ease of assembly, an
epoxy solder mask on areas not to
be soldered has been added, as well
as sockets for all memory ICs,
which provide easy installation and
removal of the ICs. Included with
the 88-S4K is a well -documented
manual with detailed theory and
troubleshooting sections and step-
by-step assembly instructions.
RAM Access Time: 200-300 ns.
(worst case) :
+5V current - 450 ma (max.)
+12V current - 290 ma (max.)
+12V current (uns elected) -
10 ina (max.)
Memory Array: 4,096 8 -bit words
Dimensions: 10" x 5"
Altair Slots: One
Price: $155.00 kit, $255.00 assem.
Availability: Within 60 days of
The 88-MUX (24-Channel Multiplexer) :
The 88-MUX, companion card to
the 88-Analog/Digital Converter (88-
ADC — see page 8 of the August issue
of C.N.) , will expand the input
capacity of the 88-ADC for applica-
tions requiring a large number of
The 88-ADC is actually a
stand-alone card for many systems,
because it contains an on-board
8-channel multiplexer. However,
for a majority of system layouts,
the real potential of the ADC and
MUX conversion system lies in the
ability of the MUX to process more
than eight signals. By using four
88-MUX cards, it is possible to
process up to 96 analog signals!
Another advantage of using the
88-MUX is the optional differential
input. With simple modifications,
the card can be set up to handle a
differential input on each channel.
As a bonus, the gain and scale
factoring of each channel can be
set independently, giving extreme
flexibility in system design. In-
put filtering can also be added to
provide the desired roll-off
An appropriate interface cable
is provided with each ADC and MUX
pair. (For more than one 88-MUX
per system, a cable is required for
each MUX card.)
Specifications for the 88-MUX (24-
Channel Multiplexer) :
Price: $319, assembled only.
Availability: within 60 days of
Gain: Up to 1000
Input Impedance: 1000 megohms
Offset: 5MV (max.)
Level: (-4 to +10v)
(-10 to +4v)
(-5 to +5v)
to .01%: 15 microseconds (max.)
P.S. requirements: +5vS40MA
(See Computer Notes, August, 1976,
page 8, for specifications jan the
88 A- to-D Converter.)
i = O 5
S Lj !z=
1 ra X R fA
: ■ ."'
; -_ ; . = : : J : : .- 1" "" -. I ; r : =. r _.
■ ■ M
= R- 1 N N N N N 5 h i 5< = & 4- « H
— |-.j i -.' — 1 --■■ = \*\ £? "x ^ = ;_• -.+ : 4.; j-j j
; " _ : P"
j_ y- -j W P 1 "-"' -=" W : j ! i ''■ = ^- ! : ~- = :■*-: '*-*
■-: ; --
C- L. EI H K J f'l H b b.. h:^ U P F"
1 J??. ."*„ _f. =": -\- ! LJ -1- PI -* f a '^" I'i
~ : ":t :
M B R K J.i'iRGE t; u r F t_
a R :
T : ~ V =z :
Example of Program printed by
Graphics Printer.(73% of full size.)
Example of Graph printed by
7000 Graphics Printer.(73% of
, m ■ , , '• , : |||: : ; • •', . ;;|||| ■ .. : : : | ; |||' : ; '■ ;1 ?|||f^ , : |iPy
Example of 3 -Dimensional House
projected by 7000 Graphics Printer.
(73% of full size.)
Users have discovered the following
mistakes in two of our software
#2-3-761 , page 18:
Memory location 1 .042 166 should
read 1 042 301
Memory location 2 015 014 should
read 2 015 013
#6-1-763, Line 570:
A=FNR(N05)+INT (N0+5) : B=FNR(Nl/20)+
INT(Nl/20) : C=FNR9L2/50)
should read A=FNR(N05)+INT (N0/5) etc.
This change makes it possible to
win the game.
2450 Alamo SE
Albuquerque, NM 87106
Continued from Page Seven —
Here are three test programs that are useful in checking out your
when running only A0 § 1 should be lit
reset and \
F0 ;wait for data
see if a
47 ;rotate right
24 ; branch
ACIA ready J
57 ; rotate
57 ; rotate
Should you need more help with
your 680b, please feel free to call
us. If you decide not to repair the
unit yourself, please send it in.
There is currently no backlog of
680b 's in repair and return should
be relatively prompt.
Reset, run, stop and sum of data should appear at address 0040.
on the side
By Wayne Cronin
As the only licensed ham at
MITS, I've been elected to edit a
new ham-oriented column for Computer
Notes . I'll be using this space to
pass along ideas for adapting com-
puters (hopefully ours!) to ham pur-
poses. That means I'll need lots of
input from readers, and I'm sure many
of you have some good ham applica-
tions ideas to share with us.
ASCII, HAMS, AND THE FCC
If you have your own computer
system, you probably have some kind
of I/O device that uses ASCII code.
If you could use your terminal to
key your rig, you could use your
computer to get in on RTTY activity,
or to communicate with another ham's
computer via radio. Unfortunately,
since current FCC regulations allow
only Baudot code transmission, you
have to use some kind of hardware or
software code conversion scheme to
accomplish either of these functions.
This is a needless complication and
a waste of processor power.
The only way to get the rules
changed is to petition the FCC. If
you're thinking of submitting a pet-
ition, here are a few things to
think over first.
Any new rules changes should be
general enough to allow us to take
advantage of future advances in the
state of the art automatically; we
don't want to have to cut more red
tape each time something new comes
along. If a proposal for a rules
change is too specific in its word-
ing, we could be neatly backing our-
selves into a corner.
As an example, let's suppose
that the FCC adopted new regulations
based on a petition by amateurs re-
questing the use of ASCII. This
could be interpreted as prohibiting
Baudot. If this happened, we would
instantly lose compatibility with
Baudot equipped DX stations, and
hundreds of U.S. hams using older
equipment would be forced to use the
same type of hardware or software
conversions we had hoped to avoid.
I really don't think that any-
body would submit such a restrictive
proposal (much less that the FCC
would adopt it) . This is just an
extreme example of the dangers of
hastily written, narrowly worded
If any of you are considering
submitting a rules change request
concerning the use of ASCII, I'd
like to hear your suggestions for a
generalized wording that would allow
us to use ASCII and Baudot now and
also leave a few "loopholes" for
future developments. (Don't forget
to consider the possible effects of
the proposed new bandwidth regula-
tions on HF computer communications.)
September Software Contest
By Stan Webb
The first place winner this
month is Kenneth Aird with his
FORTRAN Cross Assembler for the 680.
This program is beautifully written
and well documented. With the ad-
dition of this program, we now have
three FORTRAN Cross Assemblers in
our library. Consequently, we
cannot accept any more programs of
Second place goes to Keith
Fischer for his BECO Text Editor.
This program, written in Altair
BASIC, is considerably more power-
ful than the BASIC Editor, and
would be a valuable addition to a
BASIC system. The user documenta-
tion is fairly good, but it lacks
much program documentation.
Erik Mueller takes third place
with his MINOL Interpreter. MINOL
is a subset of BASIC designed to
run in less than 4K of memory. This
subset is very restrictive when com-
pared to a large BASIC, but is un-
doubtedly easier to work with than
machine language. This program was
previously published in the April,
1976, issue of Dr. Dobb's Journal
of Computer Calisthenics and Ortho-
Due to the lack of competition
in the subroutine category, no prize
will be awarded this month.
HAM SOFTWARE (and the lack of it)
If any of you have written ham
applications software for 8080 or
6800 based machines, please consider
submitting it to our software library.
If I receive any programs that aren't
excessively long, I'll try to get a
listing into Computer Notes . Some of
you may be able to contribute infor-
mation that could be used as the
basis for a ham software package.
An example would be a set of mathe-
matical formulas for predicting sate-
llite orbits. Information like this
made available through Computer Notes
could result in a lot more programs
for the library.
If you know of any nets devoted
to computer topics, please let me
know, and I will spread the word.
If you'd like to start a net, send
me your suggestions for a band and
Next month I'll talk a little
about some of my own ideas for ham
computers and software. I hope to
have lots of your ideas to talk about
also. Please write or call me at the
MITS Repair Department with your
comments and suggestions. 73.
The library has a lot of mat-
erial now, so I'd like to see our
users put more effort into writing
clean programs with good documenta-
tion. The programs that are neatly
typed on our submission forms and
that are well documented are more
worthwhile to other users than
those that are hastily done and have
FIRST PLACE MAJOR PROGRAM
Author: Kenneth Aird
Length: 41,000 bytes FORTRAN
Title: M6800 Cross Assembler
Very well written FORTRAN Cross
Assembler for M6800.
SECOND PLACE MAJOR PROGRAM
Author: Keith Fischer
Length: 150 lines Altair BASIC
Powerful Text Editor.
THIRD PLACE MAJOR PROGRAM
Author: Erik Mueller
Length: 7,000 (octal) bytes
Interpreter for a 4K subset of
Author: Alan Miller
Length: 200 lines Altair BASIC
Plays 3D tic-tac-toe.
Author: Alan Miller
Length: 7 lines Altair BASIC
Title: Numerical Integration
Numerical integration by Simpson's
method and Trapezoidal Rule.
Author: Roger Frank
Length: 7 lines Altair BASIC
Title: Memory Size
This program resets BASIC memory
sizes without restarting (for 3-2
Author: Alan Miller
Length: 5 lines Altair BASIC
Title: ARCS IN
Program to compute arcsin and arccos,
Author: Roger Frank
Length: 22 lines Altair BASIC
Title: Memory Test
Program to test unused memory.
Author: John Stanton
Length: 52 bytes
Title: 4PI0 KBD/PTR Loader
Loads data into memory from keyboard
and echoes it.
Author: J. David Green
Length: 168 lines Altair BASIC
Title: Horse Racing
A horse racing game that involves
betting on the races .
Floppy Disk (8 8-DCDD)
The 88-DCDD consists of the
Disk Controller and one Disk
Drive with an interconnect cable.
The Disk Controller consists of 2
PC boards (over 60 ICs) that fit
in the Altair chassis. The Disk
Drive unit consists of a PERTEC
FD-400, a power supply PC
board, and a Buffer/ Address/
Line Driver PC board. The Disk
Controller converts the serial
data to and from 8-bit parallel
words (one word every 32
microseconds). The Disk
Controller also controls all
mechanical functions of the disk
as well as presenting disk status
to the computer.
Software and System
Altair Disk Extended BASIC is an
enhanced version of Altair Extended
BASIC with added capabilities for saving
and loading programs, and for
manipulating data files on disk.
Altair Disk Extended Basic uses random
and sequential files for storing
information on disk.
Utility software is included with Altair
Disk Extended BASIC for copying
diskettes, initializing blank diskettes,
listing directories, etc.
Disk bootstrap loader is available on
paper tape, cassette tape, or PROM
(used with 88-PMC PROM Memory
Hard sectored format (non IBM
compatible) allows storage of over
300,000 data bytes.
Altair Disk Extended BASIC requires a
minimum of 20K of RAM memory to
PROM Disk Bootstrap loader allows
loading of Altair Disk Extended BASIC in
less than 10 seconds from the time
power is turned on.
A. Description and Features
The Disk Controller, which acts as the
interface between the Altair and the
Disk Drives, consists of 2 PC boards
that fit in the Altair chassis. They
require 2 slots in the Altair, contain
over 60 ICs, and connect to the Disk
Drives via an 18 pair flat cable. The
Controller can address up to 16 drives.
The Disk Drive Unit consists of a
Pertec FD-400 drive in an Optima case
5V high, 17" wide, and 17J4" deep
(same width and depth as the Altair
8800). Also in the Disk unit is a power
supply and a Buffer/ Address card for
selecting the drive and interconnecting
multiple disk systems. A fan is included
to maintain low ambient temperature
for continuous operation. The Disk
Drive units interconnect to each other
in daisy chain fashion and to the
controller using 18 pair flat cables and
DC-37 type 37-pin rectangular
B. Hardware Specifications
Track to track : 10 ms.
Head load and settle time : 45 ms.
Average time to read or write:
Worst case - - 1135 ms.
Rotational speed: 360 RPM (166.7
Tracks: 77 per disk
Sectoring: Hard sectored, 32 sectors
per track, 5.2 ms/sector (non IBM
Data Transfer Rate : 250,000 bits/sec.
(one 8-bit byte every 32 microseconds)
Maximum number of drives per system ; 16
Data storage capacity : 310,000
bytes per disk
Data bytes per sector: 128
Data bytes per track: 4,096
Disk Drive head life: over 10,000
hours of diskette to head contact
Disk Drive MTBF : exceeds 4,000
Disk Drive data reliability : not more
than 1 in 10 9 soft (recoverable errors# ^
1 in 10 12 hard (non-recoverable errors
Controller: 1.1 amps at + 8V unregu-
lated (from Altair bus)
Disk Drive Unit: 11 watts 50/60
Hz 117/220 VAC
Diskette: Hard sectored, 32 sectors +
index hole (Dysan #101, ITC #FD
Disk Drive Unit Weight: 40 pounds
C. Operating Principle .
The Disk Controller cards provide the
interface between the Disk Drive Unit and
the Altair bus. Serial read data from the
disk is converted into 8-bit parallel form by
the controller for transfer to memory via
the CPU. Data is written on the disk by
converting the 8-bit bytes outputted from
the Altair CPU to serial form. All read and
write data is transferred one byte at a
time through the CPU.
Disk Controller Board #1 controls I/O
address selection, sector counting, read
data, and disk status. Disk Controller Board
#2 controls disk drive addressing, write
data, and disk drive functions.
Set of controller cards
1 Disk Drive Unit
1 interconnect cable— 6 ft. long
1 Assembly and Operators Manual
1 Disk Extended BASIC Manual
1 Blank Diskette
1 Disk Drive Unit (117 VAC unless
1 Interconnect cable — 6 ft. long
1 Blank Diskette
3. Altair Disk Extended BASIC
Requires a minimum 20K of memory for
Altair Disk Extended BASIC on diskette
Altair Disk Extended BASIC Manual
Paper tape or cassette magnetic tape
bootstrap loader (specify when
4. Disk Bootstrap Loader on PROM:
Order 88-PMC (PROM Memory Card)
and DBL PROM (PROM programmed
with disk bootstrap loader routine)
5. Manuals only:
Disk Hardware Manual
Altair Disk Extended BASIC Manual
2450 Alamo S.E./ Albuquerque. New Mexico 87106
MITS, Money, and You
By Mike Hunter
MITS, the originator and leader
of the personal computing revolution,
has developed a program to further
extend support to those Altair users
living in regions where Altair retail
centers presently do not exist. The
Altair Ambassador program will offer
qualified individuals the opportunity
to be local MITS Altair representa-
tives in cities where computing
interest is large, yet the likeli-
hood of having an Altair dealership
is small due to the relative size
of the community. Thus, the Altair
Ambassador will be able to give MITS
support through the selling and ser-
vicing of Altair computing equip-
ment, for which he will receive a
commission on each sale, and be
able to do so using his home as his
place of business I Personal com-
puting will become even more per-
sonal, for the local MITS repre-
sentative will be a member of your
community- -perhaps even yourself!
If you live in a community
where an Altair retail center is not
available and you are an Altair
System owner, you have met the
first requirement on the way to
becoming an Altair Ambassador.
Another criterion is that the
Ambassador have a working knowledge
of MITS hardware and software so
that he may offer technical assis-
tance and repair capabilities to
other Altair users.
MITS will conduct weekend train-
ing sessions for potential ambassa-
dors which will include discussions
of software capabilities, repair
techniques, product scope, and sales
techniques. Each applicant will be
required to attend one weekend train-
ing session at his expense. Upon
notification of his acceptance into
the program, the Ambassador will
receive a program package including
business cards, forms, catalogues
and all current product literature.
Thus, the Altair Ambassador
will receive full support from MITS
so that he may best sell to and
service his community, while making
money at the same time. The only
investment the Ambassador need make
is travel and lodging expenses for
the weekend training session in
Albuquerque. Thus, if you own a
MITS Altair System, and reside in
a city without an Altair retail
center, you may very well be the
local computer expert whose future
is to be an Altair Ambassador.
Please write for more infor-
mation and an application form to:
Altair Ambassador Program
2450 Alamo SE
Albuquerque, NM 87106
Due to the increased
interest in developing
programs for very specific
needs, beginning next
month we'll be offering
whenever possible. Designed
to give readers an
opportunity to suggest what
programs they'd like to see
in the Altair Software Library, the
list of ideas will be published as
long as you keep providing
suggestions. We hope these
suggestions for programs will be
of particular interest to Altair
So send your ideas to
COMPUTER NOTES, and we'll pass
them on to our readers.
Continued from Page Three
The second portion of the book
brings the reader up-to-date with
chapters on "The Present and Po-
tential," "Applications" and "Gov-
ernmental Uses" of computers. In
"Justice, the Constitution and Pri-
vacy" Sam Ervin, Jr., U-S Senator
from North Carolina, raises some
interesting questions concerning
the computer's role in government
surveillance and the individual's
right to privacy. On a more humor-
ous side, Art Buchwald's "The Curse"
warns of the horrible consequences
a computer metes out when a defiant
citizen dares to fold, bend and
mutilate his phone bill and send it
(with payment) back to the company.
The book ' s final three chapters
--"The Impact of Computers," "Con-
trols or Maybe Lack of Controls"
and "Your Future" — explore the many
significant effects the computer
has upon our everyday lives and the
potential role it plays in our
country's future. Among the var-
ious articles in this section dis-
cussing both sides to the computer
questionnaire, "Computerized Dating
or Matchmaking," "Computer Crime"
and "Machines Hold Powers for Good
Interspersed among the many
informative articles are imagina-
tive poems, computer-generated
illustrations and cartoons.
Throughout the book, the famous
comic strip character Doonesbury
and his friend, Mark, marvel at the
many wonders of the computer. A
newspaper ad for computer operators
convinces them that they have found
their true vocation in life. "Earn
$7,000, impress your friends. MEET
In addition to all that humor,
intrigue and important information
to both the computer and noncomputer
specialist, The Compleat Computer
offers fictional romance about a
computer named Max who almost breaks
up a marriage. For $5.95 a copy,
who could ask for more?
Copies of The Compleat Computer
can be obtained directly from the
publishers: Science of Research
Associates, 1540 Pagemill Road,
Palo Alto, California.
Van Tassel has also published
Program Style , Design, Efficiency
Debugging and Testing (Prentice
LETTERS TO THE EDITOR
Continued from Page Two
Dear Ed. ,
I am writing this letter for two
reasons. Before I commence with the
diatribe, however, I would like to
say that I enjoy very much the 17K
Altair 8800 system that is up and
running at our house. We use the 8K
version of BASIC.
On the very first page of the
BASIC Reference Manual you state
that BASIC was originally developed
at Dartmouth University. This is
incorrect. I am a student at Dart-
mouth College ; to myself and all
other Dartmouth students and alumni
this reference to the "university"
is a slur.
The distinction, seemingly
minor, is historically and legally
quite important. In 1818 the state
of New Hampshire tried to take con-
trol of the College and turn it into
a state school. They were partially
successful, in that Dartmouth Uni-
versity was created. The University
used the same classrooms, dormitories,
and chapel as the College. Needless
to say, there was considerable unrest
from both students and faculty.
In 1819 the problem reached
the Supreme Court. Daniel Webster
(class of 1801) argued eloquently
for the College and triumphed. The
Dartmouth College case was a land-
mark decision that guaranteed the
inviolability of legal contracts.
So you see when you attribute
BASIC to Dartmouth University, you
credit an unenduring and illegal
"splinter school" of the early
1800' s. Please try to correct this
error in subsequent printings of the
When working on the Dartmouth
computer, I have found that the VAL
and STR$ functions are useful. VAL
takes a single string argument and
converts it to a constant:
■17.69. STR$ does the
Therefore, X$="625". Also useful is
the POS function, which searches a
string for the presence of another
string and returns the substring's
POS looks for the location of B$ in
A$ starting at location C in A$:
Thank you for your time.
John Sot os
Ed. Note: STR$ and VAL are present
in 8K and Extended BASIC, and the
equivalent of the POS function in
Extended BASIC Ver. 3.4 is INSCR.
CUSTOMER SERVICE NEWS
- continued from page 2
Shipping and handling charges -
Rates for continental United States
shipments - Prepaid or UPS COD:
$8.00 each for mainframes and ter-
$3.00 for up to three (3) peripheral
boards, add $1.00 per board there-
We are unable to ship COD to
Post Office Boxes
Companies or Educational Institu-
(3) APO or FPO Addresses
Foreign Countries (including
Foreign Countries (including
Canada) - Repair shipments will be
made via Emery Air Freight Collect.
Also, charges incurred for units
coming in from foreign countries to
MITS, e.g. customs charges, will be
billed as part of the customer's
repair charge. (These charges aver-
age between $30.00 and $40.00.)
Please remember to send in pay-
ment for these charges, otherwise a
delay will occur while we contact
you for payment or COD authorization.
We will accept for payment: Master
Charge, BankAmericard, money order,
personal check (three week delay for
processing) or authorization for COD
for charges under $15.00. Companies
and educational institutions should
remember to send in their Purchase
Orders authorizing repair and return
I hope this will help those of
you asking what our procedure is foi
returning items for repair. If you
have further questions, please con-
tact the Repair Department.
See you next month - Gale
Computer Notes Review, Volume I, is a collection
of reprinted articles from previous issues of
Computer Notes (April, 1975 through July, 1976).
We have eliminated all editorial, fictional and
advertising materials and have printed only the
most informative and technical articles pertain-
ing to Altair hardware (specs, modifications,
troubleshooting) and software. This 94-page book
is arranged in an 8 1 /2 x 11 format and is ready to
insert in a 3-ring binder. The price of Volume I
is $12.00. (Altair customers who have already
ordered the Update Service will automatically
receive Computer Notes Review, Volume I.)
Please send me Computer Notes Review, Volume I.
Enclosed is $ '
□ BankAmericard #_
D Master Charge # ' , : .
STATE & ZIP_
M ITS/2450 Alamo S.E., Albuquerque, N.Mex. 87106
Altair"" 16K Static
Almost too good to be true, the Altair 16K Static
RAM board is easily the most advanced memory
module yet developed for the Altair 8800, 8800a and
Four Altair 16K Static boards add up to the entire
64K of memory directly accessible by the Altair.
The Altair 16K Static board offers two surprise
features— minimal power requirements and fast access
time. One Altair 16K Static board draws less current
than any 8800 compatible 4K boards, thus four Altair
16K Static boards can be plugged into the Altair
8800 without beefing up the power supply.
The maximum access time of the Altair 16K Static
board is 215 nanoseconds, which makes this board
the fastest Altair compatible static board in existence.
The Altair 16K Static is now in full production.
Special introductory price is $765 in kit form and
MAIL THIS COUPON TODAY
Enclosed is check for $.
BankAmericard # .
| or Master Charge #
. □ Altair 16K Static □ Kit □ Assembled
' (include $3 for postage and handling)
I □ Please send free information package and price sheet.
STATE AND ZIP.
I MTTS/2450 Alamo SE/Albuquerque, NM 87106/505-243-7821
Prices, delivery and specifications subject to change. Allow up to bO days tor
2450 Alamo SE/AIbuquerque, NM 87106/505-243-7821